1. 恐惧;惊恐;恐慌
    Terror is very great fear.

    e.g. I shook with terror whenever I was about to fly in an aeroplane...
           每次坐飞机前，我都吓得直发抖。
    e.g. The day of terror ended after police used teargas and stormed the house.
           警察使用了催泪瓦斯攻入屋子以后，恐惧的一天结束了。

2. (尤指有政治目的的)恐怖活动，恐怖主义
    Terror is violence or the threat of violence, especially when it is used for political reasons.

terror的近义词

    e.g. The bomb attack on the capital could signal the start of a pre-election terror campaign.
           对首都的炸弹袭击可能标志着选举前的恐怖活动开始了。

3. 恐怖的事物
    A terror is something that makes you very frightened.

    e.g. As a boy, he had a real terror of facing people.
           小时候，他特别害怕见人。
    e.g. ...the terrors of violence.
           恐怖的暴力行为

4. 讨厌的小孩;淘气鬼;小捣蛋
    If someone describes a child as a terror, they think that he or she is naughty and difficult to control.

    e.g. He was a terror. He had been a difficult child for as long as his parents could remember.
           他是个淘气鬼，从小就不老实。

5. 完全吓不倒；让人丝毫不焦虑
    If something holds no terrors for you, you are not at all frightened or worried by it.

    e.g. Childbirth now held fewer terrors for her than it once had.
           她现在不像原来那样害怕分娩了。

6. to live in terror -> see live
    reign of terror -> see reign